I’ve had this about 8 months and it’s looked great up until the last several days. I’ve just upgraded my skimmer and changed from a pellet reactor to a fluidised reactor using Rowa - stating this just in case the cause is my unsettling the system.
All of a sudden something that looks brown has started to appear - any thoughts please?
All of a sudden something that looks brown has started to appear - any thoughts please?

